17 grammes of sugar gives 1% of alcohol in one litre of wine.

Wine yeast only tolerates 17-18% alcohol, after which it rests.

A reading of over 90 Hydrometer (with Oechslescale) degrees at the start or 75 degrees during fermentation can stop the process.

Proceed as follows:

Start the fermentation (with Oechslescale) at approx. +80 degrees (4 kg sugar in 20 litres).

When 40 degrees has been fermented (the hydrometer reads 40 degrees), add the remaining sugar (about 2 kg).